Automatic sheet feeding apparatuses are well known in the prior art. In recent years, their popularity has increased with the proliferation of word processing systems.
In many of the word processing systems marketed today, each user is provided with a keyboard and CRT display. A letter quality printer is often shared by several users and must operate without operator intervention. As such, a mechanism must be provided to feed a sheet of paper into the printer in response to a keyboard entered command.
Printers are generally quite noisy. The printer's noise level may be reduced by providing a sound insulating cover. In order to avoid the necessity of removing the cover to feed in a sheet of paper, automatic paper feeders are often provided.
Many of the automatic sheet feeders utilize one or more rollers which contact the top sheet of a paper supply. When a sheet of paper is required, the roller is activated, which serves to feed a single sheet of paper into the printing mechanism.
In order to successfully feed single sheets of paper, a constant pressure between the feed roller(s) and the paper (to be fed) should be maintained, regardless of the amount of paper remaining in the paper supply. In the prior art, maintaining constant feed roller pressure was accomplished by use of springs and solenoids which moved the feed roller(s) and/or paper supply as the size of the paper supply decreased. In addition to being expensive, such prior art mechanisms were quite inaccurate and required periodic adjustment.
It is a general object of the present invention to overcome these and other drawbacks of the prior art by providing an improved sheet feeder tray for use in an automatic sheet feeder.
It is another object of the present invention to provide an improved sheet feeder tray for use in a single feed roller automatic sheet feeder.
It is yet another object of the present invention to provide a sheet feeder tray which does not utilize springs or solenoids to adjust its position as the paper supply is depleted and which can be produced at a low cost.
It is an additional object of the present invention to provide a sheet feeder tray which pivots about a single point to adjust for depletion in the paper supply.
It is a further object of the present invention to provide a pivotable sheet feeder tray which maintains the paper supply in constant pressure with a feed roller (as the paper supply is exhausted).
These and other objects, features and advantages of the present invention will become more apparent from the detailed description of the preferred embodiment when read in conjunction with the drawings.